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<html lang="en">
<head>
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    <title>Document</title>
    <style>
        #box{
            width: 140px;
            height: 20px;
            border: 2px solid rosybrown;
            
        }
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    </head>
        <body>
            <button onclick="fu()" id="dianji">点击</button>
                <div id="box">
                </div>

        <script>
        var dianji = document.querySelector('#dianji');
        var cishu = 0 ;
        function fu() {
        cishu++;
        document.getElementById('box').innerHTML = '封校三天 快乐无边';
    }
        </script>
</body>
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